Anyone who’s regularly smoked knows that colds and flus can hit them harder than they would a non-smoker. But people who vape could be in for the same sort of trouble, according to some new (and very preliminary) research out today. It suggests that e-cigarettes can weaken the body’s ability to fend off the flu virus, though possibly in a different way than cigarette smoke does.
Researchers at the University of North Carolina at Chapel Hill conducted a trial with three groups of human volunteers: self-reported non-smokers, regular smokers, and regular e-cigarette users. All three groups were exposed to a weakened form of the flu virus—the same kind of virus used in the nasal spray flu vaccine.
In this weakened form, the virus can’t cause the flu, but the body’s immune system still responds to it like a typical viral invader. Before and after the virus dose, the volunteers had their throat and nose swabbed, and a blood sample was taken from each.
As expected, the immune systems of smokers were worse at marshaling their defences against the flu compared to non-smokers. In smokers, there were higher levels of viral messenger RNA detected, indicating the virus was able to replicate more of itself. This change wasn’t seen among e-cigarette users, though, but others were, relative to either smokers or non-smokers.
In these users, genes and proteins involved in the innate immune system—the immediate, first-line defence against infection—and antiviral response in general, were suppressed. Another response to the flu, the production of IgA antibodies specifically tailored to the flu, was weakened in people who used e-cigarettes as well.
Down the road, the authors speculated, these differences could have also dampened the body’s long-term response to the virus, known as adaptive immunity (the part of the immune system that “remembers” viruses and bacteria it’s encountered before).
“Together these data suggest that e-cigarette use and cigarette smoking differentially modify the respiratory antiviral host defence system,” the authors wrote.
There are a few big caveats to these findings. The major one is that the researchers haven’t yet published their work in a peer-reviewed journal; instead, they’re previewing their study at the annual conference of the American Thoracic Society this week.
That doesn’t mean the study is garbage (nor that peer-reviewed studies are always completely credible). It just means we have to treat its conclusions with some added caution.
That said, other research has suggested a link between a weaker immune system and e-cigarette use, including a study last year showing that vaping can directly sabotage certain immune calls and increase inflammation in lung tissue—at least in the lab.
The looming question, as with so many vaping studies though, is whether the implied effects of vaping on the body amount to significant harm. Organisations such as Public Health England have concluded that e-cigarettes, if not completely harmless, are nonetheless much less toxic than traditional tobacco cigarettes and can help smokers quit.
So even if vaping could make your immune system somewhat worse during the flu season, it remains to be seen whether its effects are negligible and/or anywhere near as bad as that of smoking.
On the other hand, some public health experts have argued there’s still much more research that needs to be done before we can be sure of anything about e-cigarettes and their potential health risks, especially long-term. They (and the FDA) have also pointed out that the dramatic rise in teen vaping is definitely not a good thing (and might even create new smokers).
So yeah, to be continued. Gizmodo has reached out to the study authors for comment and we’ll update this post when we hear back.